Water Quality Standards and NPDES Permits

TTL CEH SESSIONTUSCALOOSA, AL

MAY 20, 2015

Presentation Outline• Background

• Regulatory Framework

• Alabama’s Surface Water Quality Standards

• NPDES Permits

How Did We Get Here• Alabama Water Improvement Advisory Commission• Federal Water Pollution Control Act• Alabama Water Pollution Control Act• Clean Water Act (FWPCA Amendment 1972)• Alabama Environmental Management Act (1982)• Construction Grants• Nonpoint Source Pollution

Alabama Water Improvement Commission• Water Quality Studies – 1948

• “Studies of Pollution in Alabama Streams” – 1949• New regulatory authority granted by legislature• Additional Funding and Staff

Alabama Department of Environmental Management

• Formed in 1982• Alabama Water Improvement Commission• Alabama Department of Public Health

• Air Pollution Control• Solid Waste• Public Water Supply

WQS: Purpose• Restore and maintain the chemical, physical, and

biological integrity of the Nation’s waters• Achieve water quality consistent with the

“fishable/swimmable” goal – WHERE ATTAINABLE

WQS: Terminology• Use Classifications (ADEM Admin. Code Ch. 335-6-11)

• Designated Uses• Who are the Users

• Water Quality Criteria (ADEM Admin. Code Ch. 335-6-10)• Narrative• Numeric• Must be protective of the uses

WQS: History• Initial adoption by AWIC in 1967 (Cahaba & Warrior basins

in 1970 – 1972)• Amended ~ 30 times, most recently in 2014• Environmental Management Commission has authority to

adopt revisions• Reviewed at least once every three years (triennial review)

WQS: Significance• Goals and Objectives• Basis for regulatory programs• Framework for monitoring• Yardstick for assessment• Protect aquatic life and human health

WQS: Components• Designated Uses (Chapter 335-6-11, ADEM Admin Code

• Water Use Classifications• Special Designations

• Water Quality Criteria (Chapter 335-6-10, ADEM Admin Code• General Criteria• Classification-specific Criteria• Nutrient Criteria for Lakes

• Antidegradation Policy

Water Use Classifications• Outstanding Alabama Water (OAW)• Public Water Supply (PWS)• Shellfish Harvesting (SH)• Swimming and Other Whole Body Water-contact Sports (S)• Fish and Wildlife (F&W)• Limited Warmwater Fishery (LWF)• Agricultural and Industrial Water Supply (A&I)

Special Designations• Outstanding National Resource Water (ONRW)

• High quality waters that constitute an outstanding National resource• Little River (East and West Forks)• Weeks Bay• Sipsey Fork

• Treasured Alabama Lake (TAL)• High quality waters within impoundments or natural lakes that

constitute an exceptional resource• Lake Martin

Classification of Streams• 77,274 miles of streams in Alabama

• 97 – 98% have the classification assigned in 1967 – 1972

• Waterbodies can have multiple classifications

• Waterbodies not specifically listed are assigned the Fish and Wildlife classification

Water Quality Criteria - Narrative• ADEM Admin. Code Chapter 335-6-10-.06

• State waters shall be free from substances attributable to sewage, industrial wastes, or other wastes…oSettleablesoFloatablesoToxics

Water Quality Criteria - Numeric• Freshwater Aquatic Life

• Acute and Chronic

• Marine Aquatic Life• Acute and Chronic

• Human Health

Water Quality Criteria - Numeric• ADEM Admin Code Chapter 335-6-10-.07

• Toxic Pollutant Criteria (109 Toxic Pollutants)

• ADEM Admin Code Chapter 335-6-10-.09• Specific water quality criteria – vary by classification

• ADEM Admin Code Chapter 335-6-10-.11• Chlorophyll a Criteria for Lakes

“Ha ha ha, Biff. Guess what? After we go to the drugstore and the post office, I’m going to the vet’s to get tutored.”

Freshwater Bacteria Criteria to Protect Recreation and Water Supplies

0

500

1000

1500

2000

2500

3000

3500

OAW S PWS (summer) PWS (winter) FW (summer) FW (winter) LWF AI

Colo

nies

/100

ml

Freshwater Bacteria Criteria

Geometric Mean Single Sample Maximum

Dissolved Oxygen Criteria – Aquatic Life

0

1

2

3

4

5

6

OAW S PWS FW LWF (summer) LWF (winter) AI

Dis

solv

ed O

xyge

n, m

g/L

Dissolved Oxygen Criteria

• Human Health Criteria apply to all uses but are more stringent in PWS waters

• Criteria for most metals expressed as dissolved form

• Criteria for certain metals vary with stream hardness

Hardness-dependent metals

• Cadmium• Chromium (trivalent)• Copper• Lead• Nickel• Silver• Zinc

Water Quality Criteria

Hardness-dependent Metals Criteria

65.66

42.01

28.93

4.951.17 0.15

0

10

20

30

40

50

60

70

Zinc Chromium+3 Nickel Copper Lead Cadmium

Crite

rion,

ug/

L

Chronic Aquatic Life Criteria for Selected MetalsHardness = 50 mg/L as CaCO3

Stream Hardness Effects on Aquatic Life Criteria

0.00

2.00

4.00

6.00

8.00

10.00

12.00

10 20 30 40 50 75 100 125

Crite

rion,

ug/

L

Hardness, mg/l as CaCO3

Chronic Aquatic Life Criteria for CopperVariation with Stream Hardness

Mercury Criteria

2.4

0.012

2.1

0.025 0.04192 0.042420

0.5

1

1.5

2

2.5

3

Freshwater Acute Freshwater Chronic Marine Acute Marine Chronic Human Health PWS Human Health FW

Crite

rion,

ug/

LMercury Criteria for Surface Waters

Drives NPDES Permit Limits

Arsenic+3 Criteria

340

150

6936

0.1205 0.30300

50

100

150

200

250

300

350

400

Freshwater Acute FreshwaterChronic

Marine Acute Marine Chronic Human HealthPWS

Human Health FW

Crite

rion,

ug/

L

Arsenic+3 Criteria

Drive NPDES Permit Limits

NPDES Permit Limits for Toxics• When is a permit limit needed?• Answer:

• When the concentration in the discharge has the potential to cause the concentration in the stream to be greater than 20% of the water quality criterion. This calculation is called the “Reasonable Potential Analysis”.

Example – NPDES Permit Limit for Copper? RPA for Copper:

• What we need to know to begin• Receiving stream’s use classification• Receiving stream’s 7Q10 flow• Receiving stream’s 1Q10 flow• Wastewater flow• Receiving stream’s dissolved copper concentration

and hardness upstream of the wastewater discharge location

• Partition coefficient for copper (dissolved to total recoverable) = 0.388

Example – Hilliard N. Fletcher WWTP• Black Warrior River at Tuscaloosa, AL

• Wastewater Flow = 24 MGD (37.1 cfs) - Qd

• River 7Q10 = 220 cfs - Qr

• River 1Q10 = 55 cfs - Qr

• River Hardness = 50 mg/L as CaCO3

• Upstream Copper Concentration = 0 (assumed as background) - Cr

• Acute Freshwater Criterion for Copper = 6.99 / 0.388 = 18.02 ppb - Cs

• Chronic Freshwater Criterion for Copper = 4.95 / 0.388 = 12.76 pbb - Cs

Example – Hilliard N. Fletcher WWTP• Calculate the Allowable Effluent Copper Concentration (Cd) Using

the Acute Criterion and 1Q10 Flow – Mass Balance Equation• Cd = (CsQd + CsQr – CrQr)/Qd• Cd = (18.02*37.1 + 18.02*55 – 0*55)/37.1 (Acute criterion)• Cd = 44.73 ppb• 20% of Cd = 0.2*44.73 = 8.94 ppb• 8.94 ppb < 18.02 ppb == No Permit Limit Needed to Protect

Acute Criterion

Example – Hilliard N. Fletcher WWTP• Calculate the Allowable Effluent Copper Concentration to Using the

Chronic Criterion and 1Q10 Flow – Mass Balance Equation• Cd = (CsQd + CsQr – CrQr)/Qd• Cd = (12.76*37.1 + 12.76*220 – 0*220)/37.1 (Chronic criterion)• Cd = 88.43 ppb Copper – Total Recoverable• 20% of Cd = 0.2*88.43 = 17.69 ppb• 17.69 ppb > 12.76 ppb == Permit Limit May Be Needed to

Protect Chronic Criterion (if Copper is present in the discharge)

NPDES Permit Limits – CBOD5• Technology-based Effluent Limits or Water Quality-

based Effluent Limits• Ensures Protection of Instream Dissolved Oxygen

Concentration • Secondary Treatment = Technology-based Limits

for Publicly Owned Treatment Works• Secondary Treatment

• CBOD5 = 25 mg/L• TSS = 30 mg/L

Development of Water Quality Based Effluent Limits

• Mass balance equations• Water quality models• Mixing zone models

CBOD5 vs. Dissolved Oxygen

0

1

2

3

4

5

6

7

8

9

0 2 4 6 8 10 12

Dis

solv

ed O

xyge

n, m

g/L

Distance Downstream, miles

Dissolved Oxygen vs. Distance Downstream

CBOD5 = 25 mg/L CBOD5 = 20 mg/L CBOD5 = 15 mg/LCBOD5 = 10 mg/L CBOD5 = 8 mg/L DO Criterion

Ammonia and Organic Nitrogen• NH3-N is both a toxicant and consumes oxygen as it

is converted to NO3-N• 1 mg/L of NH3-N uses 4.57 mg/L of O2 as it is

converted to NO2-N and NO3-N

• Organic nitrogen indirectly consumes oxygen after it is converted to NH3-N

Carbonaceous and Nitrogenous O2 Demand

0123456789

0 2 4 6 8 10 12

Dis

solv

ed O

xyge

n, m

g/L

Distance Downstream, miles

CBOD5 + NH3-N + TON

CBOD5 Only CBOD5+NH3-N+TON DO Criterion

Ammonia Toxicity• NPDES Permits may contain an NH3-N limit to:

• Prevent ammonia toxicity to aquatic life• Maintain dissolved oxygen in the receiving stream

• The toxicity of NH3-N is dependent on both pH and temperature (toxicity increases with pH)

EPA Recommended Ammonia Criteria - 2013

• Recognizes sensitivity of mussels and trout to NH3-N • Include both Acute (CMC) and Chronic (CCC) Criteria• Varies with both pH and temperature

• As pH and temperature increase, criteria decrease

EPA 2013 Chronic Toxicity Criterion for Total Ammonia Nitrogen, mg/LTemperature

pH 5 10 15 20 22 24 26 28 30 326 5.13 4.23 3.06 2.22 1.95 1.71 1.51 1.32 1.16 1.02

6.1 5.10 4.21 3.05 2.21 1.94 1.71 1.50 1.32 1.16 1.026.2 5.07 4.18 3.03 2.19 1.93 1.70 1.49 1.31 1.15 1.016.3 5.03 4.15 3.00 2.18 1.91 1.68 1.48 1.30 1.14 1.006.4 4.98 4.11 2.97 2.15 1.89 1.67 1.46 1.29 1.13 0.996.5 4.92 4.06 2.94 2.13 1.87 1.64 1.45 1.27 1.12 0.986.6 4.85 3.99 2.89 2.10 1.84 1.62 1.42 1.25 1.10 0.976.7 4.76 3.92 2.84 2.06 1.81 1.59 1.40 1.23 1.08 0.956.8 4.65 3.83 2.77 2.01 1.77 1.55 1.37 1.20 1.05 0.936.9 4.52 3.72 2.70 1.95 1.72 1.51 1.33 1.17 1.03 0.907 4.36 3.60 2.60 1.89 1.66 1.46 1.28 1.13 0.99 0.87

7.1 4.18 3.45 2.50 1.81 1.59 1.40 1.23 1.08 0.95 0.837.2 3.98 3.28 2.38 1.72 1.51 1.33 1.17 1.03 0.90 0.797.3 3.75 3.09 2.24 1.62 1.43 1.25 1.10 0.97 0.85 0.757.4 3.49 2.88 2.09 1.51 1.33 1.17 1.03 0.90 0.79 0.707.5 3.22 2.66 1.92 1.39 1.22 1.08 0.95 0.83 0.73 0.647.6 2.94 2.42 1.75 1.27 1.12 0.98 0.86 0.76 0.67 0.597.7 2.64 2.18 1.58 1.14 1.00 0.88 0.78 0.68 0.60 0.537.8 2.35 1.94 1.40 1.02 0.89 0.79 0.69 0.61 0.53 0.477.9 2.07 1.70 1.23 0.89 0.79 0.69 0.61 0.53 0.47 0.418 1.80 1.48 1.07 0.78 0.68 0.60 0.53 0.46 0.41 0.36

Summary

Clean Water Act

EPA Regulations

EPA Recommended Water Quality Criteria

Alabama Water Pollution Control Act

ADEM Water Quality Regulations

Alabama Water Quality Criteria

Alabama’s Surface Water Quality Protection Program(NPDES Permitting Program)

QUESTIONS????• Contact Information –

Lynn SiskTTL, Inc. – Montgomery, ALPhone: 334 – 387 – 1586email: LSISK@TTLUSA.COM

“Notice all the computations, theoretical scribblings, and lab equipment, Norm ….Yes, curiosity killed these cats.”